Although Trichomonas vaginalis is the most common non-viral sexually transmitted infection in the world, large gaps in our knowledge concerning its most fundamental biological process still remain. The current model of the Trichomonas vaginalis life cycle illustrates mitotically dividing parasites transmitted by sexual acts, however current data suggests that genetic exchange is a likely occurrence. Although trichomoniasis is often asymptomatic, infection has been implicated in an increased incidence with HIV and associated with a variety of other serious health sequelae. Therefore, better treatment options for this parasitic infection may translate into reduced risk for severe disease. The notion of genetic exchange is particularly relevant as we consider its implications in rising resistance to metronidazole, the drug of choice in treating symptomatic infection with Trichomonas vaginalis. Using an expansive sample collection and an integrative, multidimensional approach this research application aims to elucidate the mechanism of genetic exchange in Trichomonas vaginalis, which would have huge implications for the control and treatment of this common disease. To test the hypothesis that T. vaginalis is capable of genetic exchange we propose to: 1.) Identify naturally arising recombinants from genetically mixed infections; 2.) Analyze the ploidy of numerous clinically isolated parasites and identify hybrids in order to determine the possibility of recombination by meiosis or parasexual process in nature; 3.) Investigate the regulation, expression and function of meiosis specific genes in Trichomonas vaginalis, as these genes have been shown to strictly function in meiosis or parasexual processes in all organisms in which they have been studied in depth. These studies not only hold potential to redefine how we think about Trichomonas vaginalis biology, control, and treatment but also open the door to the possibility of utilizing genetic crosses, a powerful tool with great potential which can be employed to facilitate molecular studies and begin to clarify the immensely complex assembly of the T. vaginalis genome.